Study Of Genetic And Neuronal Mechanism Governing Action Selection Between Sleep And Sexual Behavior In Drosophila

Animals have various behaviors,but in certain context,an animal executes one particular behavior among many others according to external stimuli and internal physiological state,a process sometimes referred as action selection.The mechanisms underlying such behavior choice remain to be understood.Sex and sleep are two fundamental behaviors necessary for survival and reproduction,and these two behaviors cannot be displayed at the same time.Currently,how these two competing behaviors interact with each other was poorly understood.Firstly,we demonstrate that sex and sleep affect each other in Drosophila:sleep deprivation inhibits male courtship behavior but does not affect female receptivity,while activation of sex-promoting P1 neurons suppressed male sleep,suggesting a sex-specific interaction between sex and sleep.Further,we found P1 neurons in courtship circuit functionally connect with DN1 neurons in sleep circuit:P1 activation-induced sleep decrease was achieved by forming mutually excitatory connections with sleep-controlling DN1 neurons,revealling the neuronal interaction between sex circuit and sleep circuit.Moreover,we verified that sexually dimorphic sleep was regulated by Fruitless(Fru)and Doublesex(Dsx)in sex determinant hierarchy,thus the genetic correlation was found.In addition,FruM(male-specific Fru)was found to regulate male courtship and sleep through distinct neural substrates.Together these studies reveal the genetic and neuronal basis underlying the sex-specific interaction between sleep and sexual behaviors in Drosophila,and provide insights into how competing behaviors are co-regulated.Another question we focused was how sex-specific behaviors are generated genetically.Courtship is generally considered as male specific,but we found that fru mutant females exhibit male-like courtship behavior(MLB,e.g.,following and wing extension)after several days' grouping experience,indicating that functional fru was produced in females to inhibit courtship.Furthermore,absence of sex-specific P1 promoter of fru can induce females to display such courtship-like beahvior,suggesting that the functional products in females come from P1 transcripts;but meanwhile frame shift mutations targeting P1 transcripts we generated cannot reproduce MLB,and no protein signal was detected by knocking in a tag after the first ATG of P1 transcripts,which implicates that the functional products of ruitless in females probably act in the form of RNA but not protein.These findings broaden our understanding of the function of fruitless in specifying the difference between male and female sexual behaviors.